Speed-Walking RunBot Learns to Climb with 'Eyes'

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Oct 30, 2009

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While it has yet to rival the hip-swishing jauntiness of human speed walking, last year's MIT-beating, Euro-engineered robo-walking champ still rules the two-legged robot race. And now, thanks to infrared eyes and a gait-altering neural network, this competition crushing 'bot has learned to conquer mountains, too. RunBot, developed at Germany's University of Göttingen, uses its infrared "eye" sensors to "see" hills and, after a few falls, learns to adapt his movements to climb the slope, just as toddlers do.

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"Any walker that can figure out how to adapt to different terrains and slopes is making headway toward an ideal," says Popular Mechanics' Resident Roboticist Daniel H. Wilson. "A robot designer can never predict what problems a robot will have to face, so the best approach is to design the robot to solve new challenges on its own."

But learning to mimic the quick adaptation and delicate balance of the human gait is, in fact, a tough trick for any robot. At heart, there are two components behind walking: the biomechanical design of the legs and joints, and the control and gait adaptation functions of the brain. When people walk, only one weight-bearing foot touches the ground at a time—an incredible feat considering how unstable a mobile, 6-ft., 175-pound machine would be if balanced on a single surface area of less than half a square foot. RunBot's German and Scottish creators partially solved the mechanical problem with clever hip, knee and torso specs last year; his particular biomechanical design made him fast, but now it's his eerily human-like "brain" function that makes him special.

RunBot's creators argue that the human brain "involves a hierarchy of levels" as it controls walking. That is, when humans walk the straight and narrow, walking takes little mental control. But when people walk uphill—or navigate sharp corners, or balance on icy ground—the brain kicks in at a higher level by quickly analyzing terrain and altering stride length, speed, torso angle and the like. RunBot does the same: Triggered by his falls, his infrared eye records the preceding changes in sensory input, "sees" the uphill slope coming again and shifts his center of gravity forward and shortens his steps.

But for all of his smarts, RunBot, despite his name, can't run—or walk without some support. Still, despite his Erector-Set build, RunBot's quick-flicking knees seem almost human as he marches about. Need we worry about speed-walking robots terrorizing our towns? "I wouldn't worry," says Wilson, author or How to Survive a Robot Uprising. "In the world of bipedal robotics, walking and running are strictly defined: Speed walking just means the robot will fall over if both its feet leave the ground. So if you are prone to worry, keep a close eye on running robots." —Jancy Langley